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3 Sheets-Sheet 1..

(No Model.)

P. ARMINGTON.

PISTON VALVE.

No. 370,443. Pa tented Sept. 27, 1887.

3 Sheets-Sheet 2.

(No Model.)

P. ARMINGTON.

PISTON VALVE.

Patented Sept. 27,1887.

W W H 1 henioz' zzwaaw rvoziryZ fm; %1 fi wwzrz 5 y mywdv (No Model.) 3-Sheets-Sheet 3. P. REMINGTON.

PISTONYVALVE. No. 370,443. Patented Sept. 27, 1887 NITE STATES ATENT Fries.

PISTON-VALVE.

SPECIFICATION forming part of Letters Patent No. 370,443, dated September 27, 1887.

Application filed March 1, 1887. Serial No. 229,309.

To all whom it may concern:

Be it known that I, PARDON ARMI'NGTON, of Providence, county of Providence, and. State of Rhode Island, have invented an Improvement in Piston-Valves, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

My invention relates to piston-valves for steanrengines,especially of that class wherein a high speed is desired, and has for one of its objects to construct the valve cylinder so as to provide an increased bearing-surface for the piston-valve.

The valve-cylinder referred to is provided with portopenings extended about it, and which communicate with the main cylinder,

the said port-openings registering with a main and auxiliary port in the piston-valve, thereby admitting the maximum quantity of steam to the engine-cylinder with a minimum travel of the piston-valve, the waste room in the said piston-valve being reduced to a minimum.

Prior to my invention I am aware that a piston-valve has been constructed of a single casting closed at its ends and provided with steam-ports at its center and ends, the said Valve having a bearing-surface substantially its entire length.

My invention therefore consists, essentially, in a steamengine, of the engine-cylinder, an independent valve cylinder provided with port-openings communicating with the enginecyli nder, combined with a piston-valve for the said valve-cylinder, having a bearing-surface of substantially'the length of the said cylinder and provided with openings to register with the port-openings in the said valve-cylinder, substantially as will be described.

Other features of my invention will be pointed out in the claims at the end of this specification.

Figure 1 is a longitudinal section of a portion of a steam-engine provided with my improved piston-valve; Fig. 2, a transverse section of Fig. 1 on line was; Fig.3, a section of one of the piston -valves on line 3 y of Fig. 1, and Fig. 4 a modification to be referred to.

The engine-cylinder A, as herein shown, has cast integral with it two independent valvecylinders, a a,which co-operate to form a sin- (No model.)

gle-piston valve-cylinder. Each cylinder a (1 receives within it an independent piston-valve, a a respectively, which are joined together to form a single piston-valve by a valve-stem, a", connected to any suitable or well-known valvegearing, to'operate the said pistonvalves in unison. Each piston-valve is closed at one end and open at its other end to receive live steam.

Each cylinder a a,near one end,is provided with an annular channel, b, which forms in the respective cylinders the main port-opening of cylinder-ports 1) b and near its opposite end each cylinder has an annular channel, b of smaller area in crosssection than the channel I), the channel b forming an auxiliary portopening to the cylinder-ports and being connected with the main port 1), near the top of the respective cylinders, by the passage b",and with the cylinder-ports below the bottom of the said cylinder by the passage b Each cylinder a a is made hollow and has on its inner side, as herein shown, longitudinal ribs 0, and each cylinder also has annular openings or grooves c c to register with the port-openings b b, respectively.

It will be noticed that the interior surface of each cylinder a a constitutes the seat for its piston-valve, and that the said piston-valve is substantially equal in length to the length of the said cylinder on its inner surface, consequently obtaining for the said piston-valve a bearing substantially its entirelength. The piston-valve having a bearing-surface substantially equal to its length, and being balanced, may be run very quickly and smoothly.

Referring to Figs.1 and 4, it will be seen that steam is about to be admitted to the enginecylinder through the main port I), and the auxiliary port bflcommunicating therewith, of the piston-valve a. The auxiliary port-opening 0 is of such area in crosssection, as compared with the main port-opening cof the piston-valve, that when the auxiliary port-opening 0 is fully opened, the said opening 0*,plus the amount to which the main port-opening c has been opened,equals substantially the total area in crosssection of the main port-openings, thereby admitting the maximum amount of steam to the engine-cylinder with the minimum travel of the piston-valve.

In Fig. 1 I have shown the cylinders a a as connected at their ends with the exhaust-ports d d, the steam in the engine-cylinder being quickly exhausted therefrom; but instead of having an exhaust-port located at theend of each cylinder, a common exhaust for both the ports I) b may be located between the two cylinders a a, and in this case the position of the piston-valves will be reversed, as shown in Fig. 4, as will also the arrangement of the main and auxiliary ports, the said pistonvalves taking steam at the outer ends of their respective cylinders.

I claim 1. In asteam-engine, the engine-cylinder and an independent valve-cylinder provided with port-openings 1; b connected together and communicating with the engine-cylinder, combined with a piston-valve for said cylinder having a bearing-surface of substantially the length of the said cylinder, and provided with port-openings to register with the port-openings in the said valve-cylinder, substantially as and for the purpose specified.

2. In asteam-engine, the engine-cylinder and an independent valve-cylinder provided with port-openings b I), connected together and (30111- Inunicating with each end of the engine-cylinder, combined with a piston-valve for each cylinder having abearing-surface of substantially the length of the said cylinder, and provided with openings to register with the portopenings in the said valve-cylinder, and with a valve-stem to connect both piston-valves, substantially as described.

3. In a steam-engine, the engine-cylinder and independent valve cylinders provided with port-openings b If, connected together and communicating with each end of the enginecylinder, combined with a piston-valve for each cylinder having a bearing-surface of substantially the length of the said cylinder and provided with port-openings to register with the port-openings in said Valve-cylinder, the said piston-valve having one end open to receive steam between said valve-cylinders and closed near the exhaust, and with a valve-stem to connect both piston-valves,substantially as described.

4. In a steam-engine, the engine-cylinder and independent valve cylinders provided with port-openings b b,connected together and communicating with each end of the enginecylinder, combined with a piston-valve for each cylinder, having a bearing-surface of substantially the length of the said valve-cylinder and provided with strengthening-ribs on its inner side and with port-openings to register with the port-openings in the said valve-cylinder, the said piston-valves being connected bya single Valve-stem, substantially as and for the purpose specified.

In testimony whereof I have signed my name to this specificationin the presence of two subscribing witnesses.

' PARDON ARMINGTON. .Witnesses:

, G. W. GREGORY,

J. H. CHURCHILL. 

